Condensing vacuum insulation



June 16, 1964 Filed April 225, 1962 R. B. JACOBS ETAL CONDENSING VACUUMINSULATION 2 Sheets-Sheet l Robert B. Jacobs Lewis O. Mullen DonaldA.Van Gundy Robert J. Richards Willis G. Steward,

JNVENToRs.

June 16, 1964 R. B. JACOBS ETAL CONDENSING VACUUM INSULATION Filed April2:5, 1962 2 Sheets-Sheet 2 Robert B. Jacobs` Lewis O. Mullen DonaldA.Van Gundy Robert J. Richards W|I||s G Steward,

JNVENToRs.

BY Z. f/M

United States Patent() The invention described herein may bemanufactured and used by or'for the Government for governmental purposeswithout the payment of any royalty thereon.

This invention relates to an apparatus for transfer of liquiied gases,as for example, nitrogen, oxygen, etc., and more particularly toinsulation for such apparatus.

In the transfer of liquied gases'from either the production apparatus orfrom storage containers to other receptacles it is necessary to maintainthe respective gases at low temperatures, ranging from 0 F. toapproximately 300" F. in the case of liquied oxygen. The temperaturesare lower in the case of hydrogen, nitrogen and other gases. Hence,special precautions must be taken in order to avoid losses due toevaporation which are considerable and, in the case of liquid hydrogenand oxygen, to avoid hazards such as possible combustion and explosion.It is, therefore, necessary that the delivery or transfer apparatus notonly be strong and durable, but also that its design and construction besuch that heat leakage from the ambient atmosphere to the liquied gas bekept at a minimum.

Conventional vacuum insulation to separate a cold region, from`a warmlenvironment may be either dynamic or static. In the dynamic system, Vthevacuum space is continuously pumped. This system requires a pumpingapparatus and the power to run it, be available in the vicinity of thedynamically pumped system. The main problem of the static vacuum systemcom- Y prises producing and maintaining an adequate vacuum.

In order to maintain a static vacuum, the vacuum space the vacuum spacemust be treated in some manner so that no 'appreciable amount of gas isdesorbed into the vacuum space, and the walls must be impervious toambient molecules.

It is an object of our invention to provide a means for t j must beabsolutely leak tight, the walls and contents of sulated by a gas thatis condensable responsive to the particles from being re-evaporated inthe vacuum and impairingthe effectiveness `of the insulation.

Other objects and advantages of our invention will become more readilyapparent from the following detailed description taken in conjunctionwith the accompanying drawingsV in which:

FIGURE 1 is an elevational sectional view of a transfer line andcoupling. Y

FIGURE 2 is an exploded view of the transfer line disposed'for"connection between a receiving and a dispensing tank.

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FIGURE 3 isa View along line 3-3 of FIGURE 2.

FIGURE 4 is a view along line 4-4 of FIGURE 2.

One illustrative embodiment of our invention is shown in FIGURE 1 inwhich a transfer line, generally designated at 10, is disposed forconnection` to a suitable source of liquied gas. The transfer line iscomprised of a plurality of sections 12, 14, and 16.

The receiving end 18 of the transfer line carries a female coupling 20and the opposite end or delivery end carries a male coupling 22. Thetransfer line is provided with an outer conduit and an inner conduit 24and 26, respectively.

Female coupling 20 is mounted on the periphery of outer conduit 24 andis provided with internal threading and an inwardly extending shoulder25. An insert 28 secured to the inner surface 30 of conduit 24 isprovided with an outwardly extending annular shoulder 32. An annulargroove 34 provided on the outer periphery of insert 28 is disposed toreceive an O-ring seal 36 therein.

A conduit 38 smaller in diameter than conduit 24 is secured to an innerannular surface 39 of insert 28 and extends to partially enclose and tobe secured in an annular recess 40 of a member 42. Member 42 is providedwith a pair of axial openings 44 and 46 in communication. The liquiedgas conducting conduit 26 secured in the smaller opening 46 of member 42extends therefrom into the intermediate section 14 of transfer line 10.Member 42 includes an inwardly projecting shoulder 43 against whichabuts one end 45 of conduit 26.

Conduit 26 is comprised of a pair of portions 48 and 50, portion 48extends from section 12 into the intermediate section 14 of transferline 10 and terminates just short of the middleof section 14. Portion 50vof conduit 26 is slightly spaced from the portion 48 of conduit 26 andextends out of intermediate section 14. The spacing between portions 48and 50 of conduit 26 permits expansion and contraction of the liquiiiedgas conducting conduit. A seamless bronze flexible tube 52 havingannular corrugatons is disposed around those portions 48 and 50 ofconduit 26 that is within section 14 of line 10. The flexible tubepermits the uninterrupted ow of liquied gas while permitting theexpansion and contraction.l Y

Portion 50 of conduit 26 extends from intermediate section 14 of thetransfer line and thru section 16 thereof.

i Outer conduit 24 terminates at section 16 and is secured to malecoupling 22. Coupling 22 is provided with an inwardly extending shoulder52 and external threading. A conduit 54 abuts against shoulder 52 and issecured to the inner annular surface 55 of coupling 22.

A projecting portion 57 includes conduit 54 which projects out ofcoupling 22 and encloses a portion of conduit 26 which also projectsthrough coupling 22. An end member 56 is provided with an annular recess58 and an outwardly projecting shoulder 60. Conduit 54 encloses recess58 and'abuts shoulder 60 and is soldered to member 56. Member 56 isfurther provided with a recessed portion 62 into which is positioned apair of ring members 64 and 66. Y

A vacuum seal off valve 68 is -mounted in outer conduit 24 of line 10.Valve 68 is disposed to be opened to permit charging of the space 70,between conduits 24 and 26, with a condensable gas. Y

As shown in FIGURES 1 and 2, a gas dispensing tank 72 is provided with aprojecting portion 74 similar in construction to projecting portion 57of transfer line 10.V

Projecting portion 74 includes an outer conduit 76 secured at one of itsends to tank 7.2. A male 4coupling member 77 is secured to the other endof conduit 76. An inner conduit 78, partially enclosed by conduit"76,communicates into tank `72` an`d extends therefrom. Male Conduit 87extends from ymale coupling member 77 to enclose conduit 78 and ispositioned at its end -39 into recess 86 of end member S4. The conduitmay be secured to member 84 by soldering.

End member 84 Yis provided with an outer annular `surface 91 intowhich'is positioned a'pair of ring members 90 and 92 which inhibit theflow of liquid between conduits-38 and 87. Ring member 90 is a pistonring which primarily inhibits said flow, while ring member 92 is aspring washer whichholds ring member 90 in the proper v position.

To connect the transfer line to the dispensing tank'the i receiving end18 of line-10 is slipped over projecting portion 74. Conduit 7 8 extendsinto section 12 of the transfer line and the ring members 91B and 92 areseated against the inner annular surfaceof recess 44 provided in endmember 42. Female coupling 20 is then threaded to male coupling 77 toassure Va tight leakproof seal.

As shown in FIGURE 2, a receiving tank94 is provided with a connectingportion 96 similar to section k12 of the transfer line into which isinserted the projecting portion 57 ofrtransfer line 10. A femalecoupling 98 provided on connecting vportion 96 is disposed to bethreaded to the male coupling member 22 of line 10 to complete theconnection.

Thertransfer line is provided with spacers 100 positioned around conduit26 and secured to conduit 26 to support conduit 26 throughout itslength. These spacers are preferably made of Teflon and aresubstantially rectangular in cross-section to permit the condensable gasto flow around the spacers and fill the space 70.

The space 70 is full of the condensable gas at all times and when theconnection is made between the receiving and dispensing tanks the gas isdisposed to condense responsive to the cryogenic ow through the linethus creating a vacuum in space 70.

Because the condensate may not adequately adhere to the inner conduits,the inner conduits 26 and 38 are Wrapped with a material 102, havingentrapping interstices such as laminated unbonded Fiberglas. Material102 is disposed to trap solid condensed particles of the condensing gas.Another advantage of this particular type of construction is that thesolid particles can adsorb gases. However, in conventional high vacuuminsulation, these gases would remain in the vacuum space and serve todeteriorate the vacuum insulation.

Because the trapping material has a high absorptivity for infra-redradiation, the resultant Vacuum insulation would be very poor.Therefore, a highly polished material 104, such as aluminim foil iswrapped around material 102 to provide surfaces of low absorptivity andthus `produce an insulation of high' effectiveness.

While the above discussion has been directed to a transfer lineutilizing carbon dioxide as a condensable gas this is to be taken in anillustrative sense rather .than in `a limiting sense. Obviously variousmodifcationsmaybe resorted to, such as utilizing other condensable mediafor creation of a vacuum or applying the-principles of the invention toapparatus such vas transport containers, storage tanks, valves, ete.,but these modifications are within the spirit and scope of the appendedclaims.

We claim:

1. Apparatus for oW of low temperature fluids therethrough comprising:

(a) an elongated outer tubular member having a receiving end providedwith a coupling for attachment Yto a supply of cryogenic fluid;

(b) an inner tubular member including a receiving end section disposedin communication with said supply of cryogenic 'luid and secured theretoby said coupling and disposed for cryogenic flow therethrough, 'saidinner tubular member axially disposed within said outer tubular memberto provide therewith an annular chamber; Y

(c) a condensible gas disposed in said chamber for condensationresponsive to cryogenic ilow through said inner tubular member;

(d) a material possessing entrapping interstices wrapped on said innertubular memberand disposed for adsorbing molecules of said condensiblegas for concentration thereofv at said material to provide thereon alayer of solidiiied gas enclosing said inner tubular member andproviding insulation thereto, said gas disposed to materially decreasepressure within the chamber for evacuated enclosure of said innertubular member responsive to the solidication; and

(e) a member forming a radiation shield enclosing said entrappingmaterial and said inner tubular member, said radiation shield and saidentrapping material being spaced from said outer tubular member to aidin solidifying and preventing re-evaporation of said solidified gas bykeeping said solidified gas from contact with said outer tubular member.

2. The apparatus of claim 1 wherein said entrapping material is glasswool.

3; The apparatus of claim shield is aluminum foil.

4. The apparatus as set forth in claim `1 including rectangular spacerscarried by said inner tubular member and secured to the outer surface ofsaid inner tubular member for support therein of said innertubularmember.

S. Apparatus as in claim 1 wherein said outer tubular member is providedwith a delivery end section:

(a) a coupling carried on said delivery end section for attachmentthereof to a receiving tank; and

(b) said inner tubular member provided with a delivery end sectionextending through said coupling and protruding into said receiving tank.

6. Apparatus as in claim 5 wherein said inner tubular member includes:

(a) an intermediate discontinuous section including a pair of portionsin axial alignment, one portion thereof provided with an end disposedadjacent one end of said receiving end section; and

(b) sealing means secured on said adjacent ends and disposed to inhibitcryogenic flow into said chamber.

7. Apparatus as in claim 6:-including a'flexible tube having annularcorrugations disposed around said portions and extending over the spacebetween said portions to permit expansion and contraction of saidportions.

8. Apparatus as in claim 6 wherein said sealing means includes: v

(ci) a collar mounted on said oneadjacent end of said portion andpartially enclosing said one end of said receiving end section; and

(b) a piston ring carried on said one .end of said receiving end sectionfor engagementwith said collar to inhibit said cryogenic flow into saidchamber.

`1 wherein said radiation References Cited in the le of this patentUNITED STATES PATENTS OTHER REFERENCES Cryogenics, vol. 1,'March 1961.Article by Kropschot on pages 171-176 relied on.

1. APPARATUS FOR FLOW OF LOW TEMPERATURE FLUIDS THERETHROUGH COMPRISING:(A) AN ELONGATED OUTER TUBULAR MEMBER HAVING A RECEIVING END PROVIDEDWITH A COUPLING FOR ATTACHMENT TO A SUPPLY OF CRYOGENIC FLUID; (B) ANINNER TUBULAR MEMBER INCLUDING A RECEIVING END SECTION DISPOSED INCOMMUNICATION WITH SAID SUPPLY OF CRYOGENIC FLUID AND SECURED THERTO BYSAID COUPLING AND DISPOSED FOR CRYOGENIC FLOW THERETHROUGH, SAID INNERTUBULAR MEMBER AXIALLY DISPOSED WITHIN SAID OUTER TUBULAR MEMBER TOPROVIDE THEREWITH AN ANNULAR CHAMBER; (C) A CONDENSIBLE GAS DISPOSED INSAID CHAMBER FOR CONDENSATION RESPONSIVE TO CRYOGENIC FLOW THROUGH SAIDINNER TUBULAR MEMBER; (D) A MATERIAL POSSESSING ENTRAPPING INTERSTICESWRAPPED ON SAID INNER TUBULAR MEMBER AND DISPOSED FOR ADSORBINGMOLECULES OF SAID CONDENSIBLE GAS FOR CONCENTRATION THEROF AT SAIDMATERIAL TO PROVIDE THEREON A LAYER OF SOLIDIFIED GAS ENCLOSING SAIDINNER TUBULAR MEMBER AND PROVIDING INSULATION THERETO, SAID GAS DISPOSEDTO MATERIALLY DECREAASE PRESSURE WITHIN THE CHAMBER FOR EVACUATEDENCLOSURE OF SAID INNER TUBULAR MEMBER RESPONSIVE TO THE SOLIDIFICATION;AND (E) A MEMBER FORMING A RADIATION SHIELD ENCLOSING SAID ENTRAPPINGMATERIAL AND SAID INNER TUBULAR MEMBER, SAID RADIATION SHIELD AND SAIDENTRAPPING MATERIAL BEING SPACED FROM SAID OUTER TUBULAR MEMBER TO AIDIN SOLIDIFYING AND PREVENTING RE-EVAPORATION OF SAID SOLIDIFIED GAS BYKEEPING SAID SOLIDIFIED GAS FROM CONTACT WITH SAID OUTER MEMBER.